irq.c

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/*
 *  Copyright (C) 2009-2010, Lars-Peter Clausen <[email protected]>
 *  JZ4740 platform IRQ support
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under  the terms of the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/delay.h>

#include <linux/debugfs.h>
#include <linux/seq_file.h>

#include <asm/io.h>
#include <asm/mipsregs.h>
#include <asm/irq_cpu.h>

#include <asm/mach-jz4740/base.h>

static void __iomem *jz_intc_base;

#define JZ_REG_INTC_STATUS  0x00
#define JZ_REG_INTC_MASK    0x04
#define JZ_REG_INTC_SET_MASK    0x08
#define JZ_REG_INTC_CLEAR_MASK  0x0c
#define JZ_REG_INTC_PENDING 0x10

static irqreturn_t jz4740_cascade(int irq, void *data)
{
    uint32_t irq_reg;

    irq_reg = readl(jz_intc_base + JZ_REG_INTC_PENDING);

    if (irq_reg)
        generic_handle_irq(__fls(irq_reg) + JZ4740_IRQ_BASE);

    return IRQ_HANDLED;
}

static void jz4740_irq_set_mask(struct irq_chip_generic *gc, uint32_t mask)
{
    struct irq_chip_regs *regs = &gc->chip_types->regs;

    writel(mask, gc->reg_base + regs->enable);
    writel(~mask, gc->reg_base + regs->disable);
}

void jz4740_irq_suspend(struct irq_data *data)
{
    struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
    jz4740_irq_set_mask(gc, gc->wake_active);
}

void jz4740_irq_resume(struct irq_data *data)
{
    struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
    jz4740_irq_set_mask(gc, gc->mask_cache);
}

static struct irqaction jz4740_cascade_action = {
    .handler = jz4740_cascade,
    .name = "JZ4740 cascade interrupt",
};

void __init arch_init_irq(void)
{
    struct irq_chip_generic *gc;
    struct irq_chip_type *ct;

    mips_cpu_irq_init();

    jz_intc_base = ioremap(JZ4740_INTC_BASE_ADDR, 0x14);

    /* Mask all irqs */
    writel(0xffffffff, jz_intc_base + JZ_REG_INTC_SET_MASK);

    gc = irq_alloc_generic_chip("INTC", 1, JZ4740_IRQ_BASE, jz_intc_base,
        handle_level_irq);

    gc->wake_enabled = IRQ_MSK(32);

    ct = gc->chip_types;
    ct->regs.enable = JZ_REG_INTC_CLEAR_MASK;
    ct->regs.disable = JZ_REG_INTC_SET_MASK;
    ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
    ct->chip.irq_mask = irq_gc_mask_disable_reg;
    ct->chip.irq_mask_ack = irq_gc_mask_disable_reg;
    ct->chip.irq_set_wake = irq_gc_set_wake;
    ct->chip.irq_suspend = jz4740_irq_suspend;
    ct->chip.irq_resume = jz4740_irq_resume;

    irq_setup_generic_chip(gc, IRQ_MSK(32), 0, 0, IRQ_NOPROBE | IRQ_LEVEL);

    setup_irq(2, &jz4740_cascade_action);
}

asmlinkage void plat_irq_dispatch(void)
{
    unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
    if (pending & STATUSF_IP2)
        do_IRQ(2);
    else if (pending & STATUSF_IP3)
        do_IRQ(3);
    else
        spurious_interrupt();
}

#ifdef CONFIG_DEBUG_FS

static inline void intc_seq_reg(struct seq_file *s, const char *name,
    unsigned int reg)
{
    seq_printf(s, "%s:\t\t%08x\n", name, readl(jz_intc_base + reg));
}

static int intc_regs_show(struct seq_file *s, void *unused)
{
    intc_seq_reg(s, "Status", JZ_REG_INTC_STATUS);
    intc_seq_reg(s, "Mask", JZ_REG_INTC_MASK);
    intc_seq_reg(s, "Pending", JZ_REG_INTC_PENDING);

    return 0;
}

static int intc_regs_open(struct inode *inode, struct file *file)
{
    return single_open(file, intc_regs_show, NULL);
}

static const struct file_operations intc_regs_operations = {
    .open       = intc_regs_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int __init intc_debugfs_init(void)
{
    (void) debugfs_create_file("jz_regs_intc", S_IFREG | S_IRUGO,
                NULL, NULL, &intc_regs_operations);
    return 0;
}
subsys_initcall(intc_debugfs_init);

#endif